investigate the YANG file load failure for Juniper (yang files versioning)

[hellt]

https://github.com/Juniper/yang

The versioning in the files names prevent goayng to find the imported modules

[hellt]

preliminary root cause is about having yang modules with names ending in @<date>.yang. The same issue is observed with some of the SRL modules

[hellt]

likely the issue is rooted with goyang - openconfig/goyang#141